This disclosure relates to a choke and kill system. In particular, although not exclusively, the disclosure relates to a choke and kill system for a deep-water drilling rig.
Choke and kill systems are used with drilling rigs to control a well. In particular, choke lines are used to control circulation of a well under pressure or subject to pressure fluctuations by diverting some of the flow, and kill lines are used to place a column of heavy fluid into a well bore in order to prevent flow of wellbore fluids.
Deep-water drilling rigs known in the art are installed with a pressure control apparatus known as a “blow out preventer” (BOP) and a choke and kill system rated for pressure up to 15,000 psi.
As efforts to find and prove new hydrocarbon producing reservoirs moves further out to sea and into deeper waters, it may be expected to include hydrocarbon reservoirs that can exert pressures at the BOP of 20,000 psi or more. Thus the rating of current 15,000 psi systems will be exceeded. This has led to BOPs designed for 20,000 psi or more. These recent BOP designs also require a 20,000 psi choke and kill system.
The recent BOP designs rated for 20,00 psi may require the entire drilling vessel and its drilling related systems to be enlarged to have the carrying and lifting capability to handle the extra weight associated with 20,000 psi BOPs and related choke and kill equipment. The costs to replace or enhance capability of the drilling vessel and drilling equipment to enable drilling of deeper reserves can be very large.